Wiseco PK1435 Top End Piston Kit 100mm 9.9:1 Compression for Yamaha Grizzly/Rhino 660

The Wiseco PK1435 is a complete top end piston kit engineered for the Yamaha Grizzly 660 and Rhino 660. Featuring a 100.00mm (4966M) bore and a 9.9:1 compression ratio, this kit delivers a reliable, performance-oriented solution for a full top end rebuild. Every component is purpose-built to meet or exceed OEM standards, making it an ideal choice for both recreational riders and competitive racers.

Wiseco's PK series kits feature a forged piston manufactured from high-silicon, low-expansion aerospace-grade aluminum alloy. This dedicated forging process provides a superior strength-to-weight ratio and improved heat transfer compared to cast alternatives — resulting in greater durability and extended service life under demanding conditions.

Kit Includes:

• Forged piston — CNC machined from aerospace alloy with optimal cam shape and profile for peak power output
• High-performance ring set — precision ground for consistent seal, extended service life, and sustained power
• Alloy wrist pin — precision machined for strength, reduced friction, and consistent dimensional accuracy
• Circlips — secure retention of the wrist pin for reliable operation
• Complete top end gasket kit — premium materials engineered to exceed OEM sealing standards
• Top end needle bearing — precision machined from high-quality materials for strength and reduced friction

Built on race-proven designs trusted by top race teams across Supercross, Motocross, GNCC, and more, the PK1435 gives you the confidence to push your 660 harder and longer. Whether you're refreshing a worn engine or building for performance, this kit includes everything needed to complete a top end rebuild in one package.